S1 Retro Lifer Helmet - Matte Black. S1 Helmet: The S1 Retro Lifer E-Helmet is designed, constructed and safety certified to be worn while riding your E-Bike, E-Scooter, E-Skateboard, skateboard, scooter, bicycle or roller skates.This is the S1 Retro E-Helmet which is certified to the new NTA 8776 standard and is rated for speeds up to 28 mph. The S1 Retro E-Helmet is a totally new style of helmet which- S1 Retro Lifer Helmet - Matte Black.